Python/sorts/shell_sort.py
Tan Kai Qun, Jeremy a7133eca13
Add typing (#9652)
Co-authored-by: Jeremy Tan <jeremytan@stripe.com>
2023-10-03 22:06:52 -04:00

41 lines
1.1 KiB
Python

"""
https://en.wikipedia.org/wiki/Shellsort#Pseudocode
"""
def shell_sort(collection: list[int]) -> list[int]:
"""Pure implementation of shell sort algorithm in Python
:param collection: Some mutable ordered collection with heterogeneous
comparable items inside
:return: the same collection ordered by ascending
>>> shell_sort([0, 5, 3, 2, 2])
[0, 2, 2, 3, 5]
>>> shell_sort([])
[]
>>> shell_sort([-2, -5, -45])
[-45, -5, -2]
"""
# Marcin Ciura's gap sequence
gaps = [701, 301, 132, 57, 23, 10, 4, 1]
for gap in gaps:
for i in range(gap, len(collection)):
insert_value = collection[i]
j = i
while j >= gap and collection[j - gap] > insert_value:
collection[j] = collection[j - gap]
j -= gap
if j != i:
collection[j] = insert_value
return collection
if __name__ == "__main__":
from doctest import testmod
testmod()
user_input = input("Enter numbers separated by a comma:\n").strip()
unsorted = [int(item) for item in user_input.split(",")]
print(shell_sort(unsorted))